This application is related to co-pending U.S. application Ser. No. 403,816 filed on July 30, 1982 assigned to Nippondenso Co., Ltd., now U.S. Pat. No. 4,432,322.
This invention relates generally to ignition timing control in a multicylinder internal combustion engine of a vehicle or the like, and more particularly the present invention relates to method and apparatus for controlling ignition timing for each cylinder so that ignition timing in each cylinder is optimum to obtain the highest engine output.
In an internal combustion engine, the ignition timing is generally determined so that engine output is maximum and fuel consumption is minimum from engine parameters such as engine rotational speed and intake pressure or intake airflow. However, an ignition timing determined in this way is not necessarily ideal throughout all the cylinders in a multicylinder engine because of variations or difference among individual cylinders, existing from the time of manufacturing or caused by secular change. Therefore, when a given ignition timing is set for all the cylinders commonly, the resultant engine output sometimes cannot be high enough as expected when ideal or optimum ignition timing is respectively set for individual cylinders.